1. Field of the Invention
The present invention relates to a catalyst for preparing a polyester for a toner which is used for developing electrostatic latent images formed in electrophotography, electrostatic recording method, electrostatic printing method, and the like, a polyester resin composition comprising the catalyst, and a toner comprising the polyester resin composition.
2. Discussion of the Related Art
Recently, improvement in the initial rise in triboelectric charges of the toner has been mainly desired from the viewpoint of speeding up the copy machines in a two-component toner, and from the viewpoint of miniaturization of the copy machines in a nonmagnetic monocomponent toner. Therefore, improvements in various charge control agents have been studied. For instance, organotin(IV) compounds have been numerously reported in Japanese Patent Laid-Open Nos. Sho 63-101856, Sho 61-272758, Sho 62-287260 and the like. However, satisfactory initial rise in the triboelectric charges cannot be obtained with these organotin compounds, and generation of background fogging is observed. Therefore, further improvements have been desired.
On the other hand, as a catalyst in the preparation of the polyester used as a resin binder for a toner, there has been used an organotin(IV) compound such as dibutyltin oxide, a titanium compound such as tetra-n-butyl titanate, a germanium compound such as germanium oxide, a manganese compound such as manganese oxide, or the like. However, the influences of these catalysts on the chargeability of the toner have not been satisfactorily studied.
An object of the present invention is to provide a catalyst for preparing a polyester for a toner which has excellent initial rise in triboelectric charges and is less likely to cause background fogging, a polyester resin composition comprising the catalyst, and a toner comprising the polyester resin composition.
These and other objects of the present invention will be apparent from the following description.